31" Medium Weight Jacket Zipper YKK #5 Brass ~ Separating ~ 580 Black (1 Zipper/pack) 31" Medium Weight Jacket Zipper YKK #5 Brass Separating ~ 580 Black (1 Zipper/pack) YKK brass separating zippers are made from the highest quality metal. Brass teeth and Brass Auto-Lock slider. Highest quality zipper for a medium weight jacket or coat.